1. Field of the Invention
The present invention relates to a field of video transmission, such as videophone conference system, and more particularly to a video coding device, a video decoding device, a video coding method, a video decoding method and a system thereof, which divide and hierarchically encode various video contents according to predefined criteria and then transmit them so as to ensure QoS for the transmitted video contents.
2. Description of Prior Art
In an IP-based network environment, it is difficult to effectively guarantee the video transmission quality for video conference thanks to unreliability of network transmission. Well-known methods generally adopt retransmission mechanism or add redundant information. Retransmission, however, usually increases the load on network, and in the case of adding redundant information, since video itself has a great amount of data, it is required that more redundant information has to be added to achieve more reliable guarantee for transmission quality.
At present, various video coding and decoding algorithms have been proposed, for example, Main Profile in H.264 provides a Redundant Slices technique. This technique, however, applies a same method for adding redundant information to any content information, and thus cannot effectively provide corresponding protections for different video contents. Therefore, QoS for video content cannot be guaranteed in the case of a bad network quality.